Methods and systems for controlling a SDN-based multi-RAT communication network

ABSTRACT

Methods and systems for controlling an SDN-based multi-RAT communication network. Embodiments herein disclose a wireless communication system, which can support/enable services that are currently being provided by multiple wireless communication systems. Embodiments herein disclose a wireless communication system based on SDN (Software Defined Networking). Embodiments herein disclose a network comprising of a generic control plane node. Embodiments herein disclose a method for communication between the proposed wireless communication system and existing UEs that are in use in today&#39;s 3GPP-LTE networks or IEEE 802.11 based WLANs without any changes in the mobile communication protocol. Embodiments herein disclose a method for providing services to the users, such as handover of a device from WLAN to 3GPP-LTE and vice versa.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from, IN Application Number201721008015, filed on Mar. 7, 2017, the disclosure of which isincorporated by reference herein.

TECHNICAL FIELD

Embodiments disclosed herein relate to multi-RAT (Radio AccessTechnology) based wireless communication network and more particularlyto controlling a multi-RAT based wireless communication network usingSDN (Software Defined Networking).

BACKGROUND

Different wireless communication systems are being deployed to providewireless broadband access, for example, 3GPP-LTE (3rd GenerationPartnership Project-Long Term Evolution), 3G-UMTS (3rdGeneration-Universal Mobile Telecommunications System), IEEE's(Institute of Electrical and Electronics Engineers) 802.11 based WLANs(Wireless Local Area Networks), and so on. These systems supportdifferent Radio Access Technologies (RATs) and also have differentnetwork architectures. They also provide different types of services tosubscribers and use different communication protocols. In some cases,the network architectures are proprietary and/or vendor-specific.Unfortunately, these networks are controlled and managed separately, andthere is little harmonization in these processes, which increases theoperation and management overheads substantially. Since theconfiguration and management of these different RAT based networks arehandled separately and in isolation to each other, it also results in asub-optimal network performance.

OBJECTS

The principal object of embodiments herein is to disclose a singlewireless communication system, which can support/enable services thatare currently being provided by multiple wireless communication systems.

Another object of the embodiments herein is to disclose a wirelesscommunication system based on SDN (Software Defined Networking).

Another object of the embodiments herein is to disclose a networkcomprising of generic control plane nodes.

Another object of the embodiments herein is to disclose a method forcommunication between the proposed wireless communication system andexisting UEs (User Equipments) that are in use in today's 3GPP-LTEnetworks, IEEE 802.11 based WLANs or any other RATs without any changesin the mobile communication protocol.

Another object of the embodiments herein is to disclose a method forproviding services to the users, such as handover of a UE from WLAN to3GPP-LTE and vice versa.

BRIEF DESCRIPTION OF FIGURES

Embodiments disclosed herein are illustrated in the accompanyingdrawings, throughout which like reference letters indicate correspondingparts in the various figures. The embodiments herein will be betterunderstood from the following description with reference to thedrawings, in which:

FIG. 1 depicts a communication system comprising of at least one UE, aWNC and a plurality of data plane nodes, according to embodiments asdisclosed herein;

FIGS. 2a, 2b and 2c depict examples of base stations as data planenodes, according to embodiments as disclosed herein;

FIGS. 3a and 3b depict examples of GWs (gateways) as data plane nodes,according to embodiments as disclosed herein;

FIG. 4 depicts the WNC (Wireless Network Controller), according toembodiments as disclosed herein;

FIG. 5 is an example scenario depicting the interaction between the WNC,the UEs, base stations and gateways, according to embodiments asdisclosed herein;

FIG. 6 describes the attach procedure for LTE RAT, according toembodiments as disclosed herein;

FIG. 7 depicts the procedure for Intra-LTE handover, according toembodiments as disclosed herein;

FIG. 8 depicts the WLAN admission procedure, according to embodiments asdisclosed herein; and

FIG. 9 depicts the WLAN to LTE handover procedure, according toembodiments as disclosed herein.

DETAILED DESCRIPTION

The embodiments herein and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments that are illustrated in the accompanying drawings anddetailed in the following description. Descriptions of well-knowncomponents and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. The examples used hereinare intended merely to facilitate an understanding of ways in which theembodiments herein may be practiced and to further enable those of skillin the art to practice the embodiments herein. Accordingly, the examplesshould not be construed as limiting the scope of the embodiments herein.

The embodiments herein disclose a wireless communication system, whichcan support/enable services that are currently being provided bymultiple wireless communication systems. Referring now to the drawings,and more particularly to FIGS. 1 through 9, where similar referencecharacters denote corresponding features consistently throughout thefigures, there are shown preferred embodiments.

Embodiments herein disclose a wireless communication system, which cansupport/enable services that are currently being provided by multiplewireless communication systems. Embodiments disclosed herein enable useof a single wireless communication system to provide services tosubscribers that are currently being provided by different wirelesscommunication systems such as 3GPP-LTE Third Generation PartnershipProject's (3GPP) Long Term Evolution (LTE), 3G-UMTS's ThirdGeneration-Universal Mobile Telecommunication System (3G-UMTS) or IEEE802.11 based WLAN Institution for Electrical and Electronics Engineers'(IEEE's) 802.11 based Wireless Local Area Network (WLAN) systems and soon.

Embodiments herein disclose a wireless communication system based on SDN(Software Defined Networking). Embodiments disclosed herein comprise ofa network comprising of a generic control plane entity hereinafterreferred to as a Wireless Network Controller (WNC) and data plane nodes.The WNC can perform all the functions of the control plane, as typicallyperformed by the entities present in each of the connected communicationnetworks. The entities, which are typically used to perform both controlplane and data plane functionalities (such as base stations, gateways,and so on), perform only data plane functions. This reduces thecomplexity of these entities.

Embodiments herein disclose a method for communication between theproposed wireless communication system and existing UEs that are in usein today's 3GPP-LTE networks or IEEE 802.11 based WLANs without anychanges in the mobile communication protocol.

Embodiments disclosed herein can support multiple Radio AccessTechnologies (RATs), the existing as well as future technologies like 5G(Fifth Generation wireless communication technology).

Embodiments herein disclose a method for providing services to theusers, such as handover of a device from WLAN to 3GPP-LTE and viceversa.

Embodiments herein disclose interfaces between various network nodes(control plane and data plane nodes) of the wireless communicationsystem.

FIG. 1 depicts a communication system comprising of at least one UE, aWNC and a plurality of data plane nodes. The WNC 101 can be connected toa plurality of data plane nodes 103. Examples of data plane nodes 103can be, but not limited to base stations, gateways, and so on. Examplesof base stations can be a base station corresponding to any RAT. Each ofthe data plane nodes 103 can correspond to a RAT. The data plane nodes103 can forward user plane data towards network end-points. The WNC 101can be connected to at least one UE 102; wherein the WNC 101 will enablethe UE 102 to control the flow of data related to at least one serviceusing at least one of the data plane nodes 103 connected to the WNC 101.

The WNC 101 can exchange control plane messages with the UE 102. The WNC101 can manage the data plane nodes 103 and provide configuration(s) forthe flow of data through them. The WNC 101 can exchange control planemessages with entities, such as other peer controllers (other WNCs), GWsand/or control plane nodes of other RATs.

The data plane node 103 can manage the communication with the UEs overthe radio interface. The data plane node 103 is responsible forcommunication between the UE 102 and the WNC 101 for signaling/controlplane messages. The data plane node 103 is responsible for communicationbetween the UEs 102 and other data plane nodes (such as Gateways) foruser plane data (such as application specific data, (for example, VoiceOver Internet Protocol (VOIP), video streams, Hyper Text TransferProtocol (HTTP) packets, and so on). Managing can comprise of the dataplane node 103 forwarding the user plane data to the destination(s) orat least one intermediate point, forwarding the configuration receivedfrom the WNC 101 to the UE, and so on.

Consider an example wherein the data plane node 103 is a base station(BS). The BS is a forwarding (data) plane node, which performs dataforwarding. The BS can also manage communication with the UEs 102, overthe radio interface. The BS can support RAT specific radio communicationprotocol layers. For every supported RAT, a specific type of BS isrequired. A generic BS 201 has been shown in FIG. 2a . For example,different types of BSs with their RAT specific protocol layers have beenshown in FIGS. 2b and 2c . The BS comprises of two protocol towers, afirst protocol tower for communicating with the UE and a second protocoltower for communicating with the core network. The UE facing stack isRAT specific in nature. For example, the protocol stack of the LTE BaseStation 202 (as depicted in FIG. 2b ) towards the UE side comprises ofPDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC(Media Access Control) and PHY (Physical) layers. The protocol stack ofthe WLAN Base Station 203 (as depicted in FIG. 2c ), the protocol stackcomprises of the L2 (MAC) and L1 layers, towards the UE. The protocolstack facing the core network is IP based and switching can be done atLayer 2/3/4, as per the requirement. The BS comprises of an interfacefor communicating with the WNC 101, which can comprise of receivingconfigurations related to flow management and other radio parameters andsending statistics to the WNC 101. The interface with WNC 101 can alsobe used to carry the messages from/to UEs.

Consider an example where the data plane node 103 is a gateway. Gatewaysare forwarding (data) plane nodes in the network, which handle packetforwarding for UEs belonging to every supported RAT. Based on thetraffic flow (path) configuration provided by the WNC 101, the gatewaysswitch/route and forward packets towards network end points. Thegateways have the capability to switch and forward data at differentlayers, (Layer 2, Layer 3, Layer 4 and so on) and support differentprotocols. The gateways may have a first interface for interacting withexternal networks and a second interface for interacting with other dataplane nodes (such as a BS) for forwarding data. For the exchange ofcontrol messages (typically flow configuration), the gateways cancomprise of a third interface towards the WNC 101. FIGS. 3a and 3bdepict two example types of gateways; a MAGW (Mobility AnchoringGateway) and a PNG (Packet Network Gateway) respectively. As depicted inFIG. 3a , the MAGW serves as an anchor point for UE mobility across thewireless network. This gateway interfaces with other data plane nodes(such as a BS) on one side and the PNG on the other side. The PNG servesas an entry point for packet data network to which the UE is connected.For every packet data network, there can be a separate Packet NetworkGateway node in the network.

FIG. 4 depicts the Wireless Network Controller (WNC). The WNC 101 cancomprise of three layers: a Software Defined Networking (SDN) middleware401, a RAT specific control layer 402, and an application layer 403. TheSDN middleware 401 manages the interface for communication with dataplane nodes 103 and peer-to-peer communication interface with other WNCsand other non-supported RATs. The SDN middleware 401 comprises of a RATabstraction module 401 a and flow configuration module 401 b. The RATabstraction module 401 a can translate RAT specific details into amessage format that could be used by the flow configuration module 401 bto configure and setup the traffic flows. The SDN middleware 401 alsocomprises of an interface 401 c, towards peer controllers (other WNCs),GWs and/or control plane nodes of other RATs.

The WNC 101 can perform control decisions and configurations for therespective data plane nodes 103. In an example, the WNC 101 can performRadio Resource Control, as performed typically by a LTE eNB (evolvedNodeB).

The RAT specific control layer 402 manages RAT specific control planelogic for control plane communication with the UEs through the BS and/orthe data plane nodes 103 (BS). The RAT specific control layer 402 andthe BS handle the protocols for communication with the UEs 102. There isone such RAT specific module for each of the RATs supported by the WNC101.

The application layer 403 manages generic application logic, common toall radio access technologies, admission control, network loadbalancing, mobility control, power control, interference management,policy configuration, authentication, security configuration and so on.

The WNC 101 can perform functions such as flow (path) configuration atforwarding (data) plane nodes 103, system information broadcast control,RAT specific signaling control, admission control, authentication andsubscriber validation, security (such as ciphering, encryption,integrity protection control, and so on), mobility control (idle-modemobility and connected-mode mobility control), network load balancing,power control and interference management, and scheduling and policymanagement.

The flow configuration function of the WNC 101 configures the individualdata flow properties, such as the Quality of Service (QoS), data rate,flow path and so on.

Broadcast information control allows the WNC 101 to broadcast relevantsystem information in a network administrative area through the dataplane nodes 103 (BS) to allow UEs to discover and connect to thenetwork.

The WNC 101 handles various RATs, which have their individual controlsignaling mechanism requirements. The WNC 101 is responsible foremulating the RAT specific signaling required for communication with theUEs.

The admission control function of WNC 101 allows it to admit/reject newUEs and new traffic (data) flows into the network. The authenticationand subscriber validation functionality of WNC 101 authenticates a UE102 and validates whether the UE 102 is entitled to a particularservice.

The WNC 101 instructs the data plane nodes 103 and the UEs 102 toencrypt the signaling and the data flows passing through the network forenhanced security. It also provides configuration to protect theintegrity of the messages.

The WNC 101 is responsible for performing idle-mode and connected-modemobility management. The WNC 101 can keep track of the location of theUEs 102 in idle-mode and can page the UE 102 if there is a request forthe UE 102. In the connected mode, the WNC 101 can manage the handover,when the UE 102 moves across network coverage areas of the BSs.

The WNC 101 can perform network load balancing. The WNC 101 can considerexisting load status of the data plane, while admitting/allocating newtraffic (data) flows in the network. The WNC 101 can use the loadinformation to re-distribute the flow of traffic from heavily loadeddata plane nodes 103 to nodes 103 that are lightly loaded.

The WNC 101 can control the transmit power of the UEs 102 and the dataplane nodes 103 (BS) administered by it in order to limit the level ofinterference in the network and increase the network coverage andcapacity.

The WNC 101 can perform scheduling and policy management. There arevarious types of traffic in the network, which require the network tosupport different bit rates, delay budgets, packet drop rates and errorrates. For example, real time traffic, such as VOIP, video streaming andso on, typically have lower delay budgets, but can tolerate higher errorrates whereas http based web browsing sessions can tolerate longerdelays, but require lower error rates. The WNC 101 can schedule varioustypes of traffic in the network and tries to ensure that the QoSrequirements of different traffic flows are satisfied.

In an embodiment herein, the WNC 101 can be deployed in a Cloud basedinfrastructure.

FIG. 5 is an example scenario depicting the interaction between the WNC,the UEs, base stations and gateways. The WNC 101 can be connected to aplurality of BSs and gateways. Each of the BS data plane nodes 103 maycorrespond to a RAT. The BS and gateways can forward user plane datatowards network end-points. The WNC 101 can be connected to at least oneUE 102, wherein the WNC 101 will enable the UE 102 to avail servicesusing the BS and the gateways. The WNC 101 can control the BS and thegateway and provide them with configuration(s) for the flow of datathrough them.

Embodiments herein use the terms “WNC” and “controller” interchangeablyand both the terms refer to the WNC 101.

FIG. 6 describes the attach procedure for LTE RAT. The signalingmessages between the UE and the network remain unchanged allowing theusage of existing LTE UEs, available in the market, with the wirelesscommunication system proposed here. In step 601, the controller 101(WNC) sends the details of the System Information Broadcast message (MIBand SIB), synchronization signals, reference signals, and so on to theLTE BS 202. In step 602, the MIB and SIB messages along with thereference and synchronization signals are broadcasted by the LTE BS 202in the cell administered by it. The MIB and SIB messages contain cellaccess and other related parameters. When the UE powers on, itsynchronizes with the network (a cell in its vicinity) with the help ofthe above-mentioned broadcast signals and messages (downlink). In step603, the UE sends a RACH (Random Access Channel) request using asignature sequence called a RACH Preamble, for uplink synchronizationand to attach to the network. In step 604, on receiving the RACHPreamble, the LTE BS 202 forwards a RACH attempt to the controller 101.The controller 101 allocates a temporary identity to the UE, which ismade permanent after completion of the successful RACH procedure. Thepermanent identity is hereinafter referred to as CRNTI (Cell RadioNetwork Temporary Identifier). In step 605, on successful RACH attempt,the controller 101 allocates uplink resources for the UE and sends theallocation message to the LTE BS 202. In step 606, the LTE BS 202responds to the UE by sending out the RACH response message. Thetemporary identity along with uplink resources is transmitted to the UEas part of RACH Response (to enable further communication between the UEand the network). In step 607, the UE then sends out an RRC (RadioResource Control) connection request to the LTE BS 202. The LTE BS 202is transparent to this message and forwards it to the controller 101. Instep 608, the controller 101 transmits the RRC connection setup messagein response to the connection request. This contains the configurationdetails of dedicated signaling radio bearer (used for further over theair communication between UE 102 and LTE BS 202). In step 609, once theRRC connection setup message has been received by the UE, it sends outthe RRC connection setup complete message, which contains the attachrequest. As part of the handling of the RRC connection setup and attachprocedures, the controller 101 may initiate an admission controlfunction also and admit a UE only if there are enough resourcesavailable to handle the UE. In step 610, the UE sends the UE identityresponse message containing the IMSI (International Mobile SubscriberIdentity), in response to the identity request sent by the controller101. The UE identity can be transferred in an encrypted manner. In step611, the UE transmits its configuration as a message to the controller101, which is then authenticated by the controller 101 by sending it tothe Home Subscriber Server (HSS). This message is transmitted only inthe absence of UE context in the network, if the attach request was notintegrity protected or in case of the failure of integrity check. Thisis done by the controller 101 in conjunction with the HSS. In step 612,the new controller 101 sends out a delete session request message to theold controller 101 to which the UE was attached, if there are activebearer contexts in the old controller 101 for the particular UE. Inresponse, the old controller 101 deletes the session. In step 613, thecontroller 101 then sends a DHCP (Dynamic Host Configuration Protocol)Request for UE IP address allocation to the DHCP server. In step 614,the controller 101 configures the data flow paths between the LTE BS 202and other data plane nodes, the gateways 103 such as MAGW and PNG. Thegateways 103 create a new entry in its EPS (Evolved Packet System)bearer context table and returns data flow response with the requiredinformation. In step 615, on completion of the data flow pathconfiguration, the controller 101 sends out the RRC connectionreconfiguration message (along with the attach accept message) to theUE. This message contains the EPS radio bearer identity and the attachaccept message containing the DHCP allocated IP address for PDN (PacketData Network) connectivity for the UE 102, as specified in step 613. Instep 616, the UE 102 replies back to the controller 101 with the RRCconnection reconfiguration complete message. Once the UE 102 obtains aPDN Address, the UE 102 can send uplink packets towards the LTE BS 202,which then uses the pre-configured data flow path for transferring thedata towards the external PDN through the GWs 103.

FIG. 7 depicts the procedure for Intra-LTE handover. The proceduresdepicted in FIG. 7 are carried out when the UE is mobile and handoveroccurs between the two LTE BSs 103. In step 701, the controller 101gathers the radio statistics from the UE in the form of measurementReport messages through the LTE BS 202. These measurements help incontrolling the connection mobility of the UE. The rules set by thecontroller 101 decide the content of the report. The controller 101 thentakes the decision on the target BS 103 to which the UE is to be handedover. The controller 101 performs admission control function and maytake the load of the different cells into account before selecting thetarget cell (BS). In step 702, downlink/uplink (DL/UL) flows are createdfor data transfer and data forwarding, once the admission controlprocedure is completed, the controller 101 sets up the data flowconfiguration in both the UL and DL directions at the target BS. In step703, RRC connection reconfiguration message including the mobilitycontrol information is sent to the UE 102 by the controller 101. In step704, the controller 101 modifies the DL/UL flows at the source BS 103for forwarding data from the source BS to the target BS. In step 705,new DL flows to the target BS 103 are created at the MAGW, but the MAGWcontinues to use the old flow to the source BS till it is asked todelete the old flow by the controller 101. In step 706, the UEsynchronizes with the target BS and accesses the target cell using RACHprocedure. The UE configures security algorithms to be used in thetarget cell after deriving target eNB specific keys. In step 707, oncethe UE 102 has successfully accessed the target cell, it sends an RRCReconfiguration Complete message to the controller 101 along with thebuffer status report through the target BS 103. This marks the end ofdata DL transmission through the source BS 103. In step 708, thecontroller 101 then sends a message to the source BS 103 instructing itto delete the UL flows and sends a message to MAGW 301 to delete the oldflows towards source BS. Once the above message is received at the MAGW301, it inserts a DL end marker packet on the old flow towards thesource BS 103 and then proceeds to delete the old DL flow. Once theabove message is received at the source BS, the source BS inserts an endmarker packet at the end of the UE UL flow to be forwarded to the targetBS. In step 709, the source BS forwards the UL/DL data for the existingflow to the target BS till it reaches the end marker packets in eachdirection. The target BS buffers non-forwarded data packets thatdirectly arrive on the UL and the DL until the end market packet fromthe target BS 103 is received. In step 710, the target BS 103 sends theend marker received notification packet to the controller 101 onreceiving the end marker packets. In step 711, the DL data flow on thesource BS 103 is deleted along with the data forwarding flows on thetarget BS 103. The target BS 103 can now transfer buffered as well asnew UL/DL data to/from the UE 102.

FIG. 8 depicts the WLAN admission procedure. In step 801, a MobileStation (STA) sends a probe request, when it wants to gather informationabout other Wi-Fi devices. Embodiments herein refer to the STA and theUE interchangeably and both the aforementioned terms refer to the samedevice. When an STA 102 wants to join a wireless network, it sends proberequests on a Wi-Fi channel, and waits for a WLAN BS 203 in range, andoperating on that channel to respond. If the STA 102 receives noresponse, it moves on to the next Wi-Fi channel. The WLAN BSs 103 inrange respond to this probe request by sending a probe response. Theprobe response contains the WLAN BS's Service Set Identifier (SSID),supported data rates, and other parameters, based on which the STA 102decides whether to join the WLAN BS's wireless network. In step 802, anySTA 102 that sends an open authentication request, is allowed to connectto the wireless network. In step 803, the STA 102 now attempts toassociate with the WLAN BS 203, by sending an association request. TheWLAN BS 203 forwards the association request to the controller 101,which then decides whether to allow the STA 102 to connect to the WLANBS 203. The WLAN BS 203 then conveys the controller 101's decision tothe STA 102 using the association response frame. In step 804, thecontroller 101 transmits identity request messages, to which the STA 102responds with a response frame, containing an identifier for the STA102. This identity is verified by the AAA (Authentication,Authorization, and Accounting) server. In step 805, the controller 101configures data flows at the data plane nodes, the WLAN BS 203, the MAGW301 and the PNG 302. In step 806, the STA 102 obtains an IP address fromthe DHCP server and starts using it for further communication.

FIG. 9 depicts the WLAN to LTE handover procedure. In step 901, the UE102 associates with the system through a WLAN BS 203 as described in theWLAN admission procedure. In step 902, the GW 103 are configured suchthat there exists a data path between the WLAN BS 203 with which UE 102is associated and the GW 103. In step 903, an IP address is allocated tothe UE 102 (based on DHCP discover and DHCP Response). In step 904, aRRC connection is setup between the UE and the network as described inLTE attach procedure of the new network once the UE 102 comes in thevicinity of the LTE BS 202 and decides to handover from WLAN to LTE. Instep 905, an attach request is forwarded to the controller 101 in orderto modify the data flow path with session continuity. In step 906, inthe absence of existing UE context or the lack of integrity protectionof the attach request or in case of integrity check failures,authentication and security is setup to activate integrity protection.In step 907, the target LTE BS is configured to forward DL/UL datato/from the UE from/to the network. In step 908, data flows (forwardingtunnels both in UL and DL) are setup between the Source BS (WLAN BS) andthe target BS (LTE BS) to forward the data intended for the UE/GWtowards the target BS by the source BS so that the data can be deliveredin sequence to the UE/GW through the target BS. In step 909, the UE 102establishes a connection in the LTE network after completing the attachprocedure. In step 910, the GWs are configured to create data flow forthis UE 102 towards the target BS 103 and delete the old data flowtowards the old BS 103. The GW 103 stops forwarding the DL data towardsthe source BS 103 and starts sending the data towards the target BS 103.It inserts an end marker packet as the last packet towards the source BSin DL before deleting the old DL flow towards the source BS 103. In step911, the source BS 103 is asked to delete the Uplink (UL) data flow pathfor the UE 102 towards the GW 103. Before deleting the UL flow, thesource BS 103 forwards all UE specific UL data towards the target BS 103using the forwarding tunnel and inserts an end marker packet at the endto indicate the completion of data transfer. In step 912, after data hasbeen completely transferred from the source BS 103 to the target BS 103with respect to this particular UE 102, the controller 101 is informedwith end marker message by the target BS 103 (after it receives the endmarker packets on the forwarding tunnel). In step 913, in response, thecontroller 101 deletes the forwarding data flows between the target BS103 and the source BS 103 intended for this particular UE 102.

Embodiments herein disclose a unified, centralized and simplifiednetwork architecture, finer/granular control over deployment ofpolicies/services in the network and seamless integration of differentradio access technology based networks within a single SDN framework.

Embodiments disclosed herein also bring a simpler forwarding planearchitecture along with a unified/centralized control planearchitecture, enabling an integrated and harmonized control/managementof the network and paving the way for optimized resource utilization andreduced management/operation overheads in the network.

Embodiments disclosed herein result in a well-defined separation betweenthe control and the forwarding (data) planes, facilitating thedevelopment of interoperable network equipment.

Embodiments disclosed herein do not require any changes in the existingUE. A UE, compliant to the existing technologies, shall be able to availall services from the proposed system, which are currently beingprovided by the existing systems and also exchange existingsignaling/data plane messages with the proposed system.

Embodiments herein simplify existing network architectures and unifymultiple RAT based systems into a single system. It has the capabilityto support/enable various RATs at the same time, reducing the need forindividual RAT controllers and thus the number of nodes in the networkis minimized. Embodiments disclosed herein do not require any change onthe UE side, as the signaling from the UE perspective is unchanged.Also, embodiments disclosed herein enable handling of multiple RATs at asingle node; more efficient handling of data offloads across RATs andregulation of the network traffic in a better way. Embodiments disclosedherein provide for a centralized control means, hereby enablingfunctions, such as, network load balancing or interference management tobe performed in a more efficient manner, which otherwise requirecoordination across multiple control plane nodes in the existingnetworks.

The above centralized architecture also makes it easier to dynamicallymanage the network by using automation, which is difficult in thecurrent day distributed systems.

The embodiments disclosed herein can be implemented through at least onesoftware program running on at least one hardware device and performingnetwork management functions to control the network elements. Thenetwork elements shown in FIGS. 1, 2, 3, 4 and 5 include blocks whichcan be at least one of a hardware device, or a combination of hardwaredevice and software module.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the embodiments herein that others can, byapplying current knowledge, readily modify and/or adapt for variousapplications such specific embodiments without departing from thegeneric concept, and, therefore, such adaptations and modificationsshould and are intended to be comprehended within the meaning and rangeof equivalents of the disclosed embodiments. It is to be understood thatthe phraseology or terminology employed herein is for the purpose ofdescription and not of limitation. Therefore, while the embodimentsherein have been described in terms of preferred embodiments, thoseskilled in the art will recognize that the embodiments herein can bepracticed with modification within the spirit and scope of theembodiments as described herein.

We claim:
 1. A method for managing communication for at least one deviceconnected to at least one Radio Access Technology (RAT) by a WirelessNetwork Controller (WNC) (101), wherein the at least one RAT comprisesof at least one data plane node (103), the method comprising forwardingcontrol plane data to the WNC (101) by the at least one data plane node(103), upon the at least one data plane node (103) receiving the controlplane data, wherein the control plane data belongs to a plurality ofRATs; managing control plane data by the WNC (101), upon receiving thecontrol plane messages from the at least one data plane node (103); andmanaging user plane data by the at least one data plane node (103). 2.The method, as claimed in claim 1, wherein managing the at least onedata plane node (103) by the WNC (101) comprises providing at least oneconfiguration to the at least one data plane node (103) for the flow ofdata through the at least one data plane node (103).
 3. The method, asclaimed in claim 1, wherein managing the control plane data by the WNC(101) comprises exchanging at least one control plane message with atleast one entity, wherein the entity is at least one of peercontrollers, gateways and control plane nodes of other RATs.
 4. Themethod, as claimed in claim 1, wherein managing the user plane data bythe at least one data plane node (103) comprises forwarding the userplane data to at least one User Equipment (UE) (102) and other dataplane nodes (103); and forwarding the at least one configurationreceived from the WNC (101) to the at least one UE (102).
 5. The method,as claimed in claim 1, wherein the at least one data plane node (103) isa Base Station (BS), the BS comprising of a first protocol tower forcommunicating with the at least one UE (102); a second protocol towerfor communicating with a core network; and an interface forcommunicating with the WNC (101).
 6. The method, as claimed in claim 1,wherein the at least one data plane node (103) is a gateway, wherein thegateway comprises at least one of a second interface for interactingwith the other data plane nodes; and a third interface for interactingwith the WNC (101).
 7. The method, as claimed in claim 6, wherein thegateway further comprises a first interface for interacting with atleast one external network.
 8. The method, as claimed in claim 1,wherein the WNC (101) comprises a Software Defined Networking (SDN)middleware (401), a RAT specific control layer (402) for each RATsupported by the WNC (101), and an application layer (403).
 9. Themethod, as claimed in claim 8, wherein the SDN middleware (401)comprises a RAT abstraction module (401 a); a flow configuration module(401 b); and an interface (401 c) towards the peer controllers; gatewaysand control plane nodes of other RATs.
 10. The method, as claimed inclaim 9, wherein the RAT abstraction module (401 a) translates RATspecific details into a message format.
 11. The method, as claimed inclaim 10, wherein the flow configuration module (401 b) configures andsets-up traffic flows using the translated message format.
 12. Themethod, as claimed in claim 8, wherein the RAT specific control layer(402) manages RAT specific control plane logic for control planecommunication with at least one external entity, the at least oneexternal entity comprising at least one UE; and a RAT specific BS dataplane node (103).
 13. The method, as claimed in claim 8, wherein theapplication layer (403) manages generic application logic, common to allRATs.
 14. The method, as claimed in claim 8, wherein the method furthercomprises of the WNC (101) performing at least one of configuration ofindividual data flow properties for the at least one RAT using a flowconfiguration function; broadcasting relevant system information in anetwork administrative area using the at least one data plane node (103)using broadcast information control across the at least one RAT;emulating the RAT specific signaling required for communication with theat least one UE (102); at least one of admitting and rejecting the atleast one UE (102) and new traffic flows using an admission controlfunction, wherein the admission control function comprisesauthenticating and validating the at least one UE (102); instructing theat least one data plane node (103) and the at least one UE (102) toencrypt signaling and the data flows; performing idle-mode andconnected-mode mobility management across the at least one RAT;performing network load balancing across the at least one RAT; limitinglevel of interference in the network and increasing the network coverageand capacity by controlling transmit power of the at least one UE (102)and the BS across the at least one RAT; and performing scheduling andpolicy management across the at least one RAT.
 15. The method, asclaimed in claim 1, wherein the method does not require any changes tothe at least one UE (102).
 16. The method, as claimed in claim 1,wherein the method further comprises performing an attach procedure,when the at least one data plane node (103) is a Long Term Evolution(LTE) BS, the method further comprises sending details of a SystemInformation Broadcast message (MIB and SIB messages), synchronizationsignals and reference signal by the WNC (101) to the LTE BS (103),wherein the MIB and SIB messages comprises cell access relatedparameters; broadcasting the MIB-SIB messages, the reference signals,and synchronization signals by the LTE BS (103) in the cell administeredby the LTE BS (103); synchronizing by the at least one UE (102) with theLTE BS (103) using the MIB-SIB messages, the reference signals, andsynchronization signals; sending a RACH (Random Access Channel) requestusing a RACH Preamble for uplink synchronization and to attach to thenetwork by the at least one UE (102); forwarding a RACH attempt to theWNC (101) by the LTE BS (103), on receiving the RACH Preamble from theat least one UE (102); allocating a temporary identity to the at leastone UE (102) by the WNC (101); allocating uplink resources for the atleast one UE (102) by the WNC (101); sending an allocation message tothe at least one LTE BS (103) by the WNC (101); sending a RACH responsemessage by the LTE BS (103) to the at least one UE (102), wherein theRACH response message comprises of the temporary identity and uplinkresources; sending a RRC connection Request to the LTE BS (103) by theat least one UE (102); forwarding the RRC connection Request to the WNC(101) by the LTE BS (103); assigning a permanent identity (Cell RadioNetwork Temporary Identifier (RNTI) (CRNTI)) to the at least one UE(102) by the WNC (101), upon completion of the successful RACHprocedure; transmitting an RRC Connection Setup message by the WNC (101)in response to the RRC connection Request, wherein the RRC ConnectionSetup message comprises configuration details of signaling radio bearer;sending an RRC Connection Setup Complete message by the at least one UE(102), upon receiving the RRC Connection Setup message, wherein the RRCConnection Setup Complete message comprises an Attach Request; sending aMobile Equipment (ME) identity Response message by the at least one UE(102) to the WNC (101); transmitting a configuration of the at least oneUE (102) to the WNC (101) by the at least one UE (102); authenticatingthe at least one UE (102) by the WNC (101) using a Home SubscriberServer/Authentication, Authorization and Accounting Server (HSS/AAA);sending a delete session request message to a controller to which the atleast one UE (102) was attached by the WNC (101), if there are activebearer contexts in the old controller 101 for the at least one UE (102);sending a Dynamic Host Configuration Protocol (DHCP) Request for UE IPAddress allocation to a DHCP server by the WNC (101); configuring atleast one data flow path between the LTE BS (103) and at least one otherdata plane node (103); sending out an RRC connection reconfigurationmessage to the at least one UE (102) by the WNC (101), upon completionof the data flow path configuration, wherein the RRC connectionreconfiguration message comprises an Evolved Packet System (EPS) RadioBearer Identity and a Packet Data Network (PDN) address; replying to theWNC (101) with the RRC Connection Reconfiguration complete message bythe at least one UE (102); sending uplink packets to the LTE BS (103) bythe at least one UE (102), on receiving the PDN (IP) address; and usingthe configured data flow path by the LTE BS (103) for transferring thedata towards the external PDN through the gateways.
 17. The method, asclaimed in claim 1, wherein the method further comprises performingintra-LTE handover of a UE (102) from a source BS (103) to a target BS(103), the method further comprises gathering radio statistics from theUE (102) by the WNC (101), wherein the radio statistics can be in theform of measurement Report messages; deciding the target LTE BS (103) towhich the UE (102) is to be handed over by the WNC (101); performingadmission control procedure; creating downlink/Uplink (DL/UL) flows atthe target LTE BS (103) by the WNC (101); setting up data flowconfiguration in the Uplink (UL) and Downlink (DL) directions at thetarget BS (103) by the WNC (101) for receiving the forwarded data fromthe source LTE BS (103); performing RRC Connection reconfiguration bythe WNC (101); sending the RRC Connection reconfiguration comprisingcontrol information for mobility to the UE (102) by the WNC (101);modifying DL/UL flows at the source BS (103) for forwarding data fromthe source BS (103) to the target BS (103) by the WNC (101); creatingnew DL flows towards the target LTE BS (103) at a Mobility AnchoringGateway (MAGW) (301) by the WNC (101); deleting old flows to the sourceBS (103) by the WNC (101); synchronizing with the target BS (103) andaccessing a target cell to which the target BS (103) belongs using RACHprocedure by the UE (102); configuring security algorithms to be used inthe target cell after deriving target eNB specific keys by the UE (102);sending an RRC Reconfiguration Complete message to the WNC (101) with abuffer status report by the UE (102), upon the UE (102) successfullyaccessing the target cell through the target LTE BS (103); sending amessage to the MAGW 301 of the source LTE instructing the MAGW (301) todelete the old DL flow towards source BS (103) by the WNC (101);inserting a DL end marker packet on an old flow towards the source BS(103) and then deleting the old flow at a gateway (MAGW) (301); sendinga message to the source LTE BS (103) instructing the source LTE BS (103)to delete the UL flow by the WNC (101); inserting an end marker packetat the end of a UE UL link flow to be forwarded to the target LTE BS(103) by the source LTE BS (103); forwarding UL/DL data for an existingflow to the target LTE BS (103) by the source LTE BS (103); bufferingnon-forwarded data packets that directly arrive on the UL and the DL bythe target LTE BS (103), until the end market packet from the source LTEBS (103) is received; forwarding an end marker received notification bythe target BS (103) to the WNC (101); deleting DL data flow on thesource BS (103) and the data forwarding flows on the target BS (103);and transferring of buffered and new UL/DL data from/to the UE by thetarget LTE BS to/from the gateway (103).
 18. The method, as claimed inclaim 1, wherein the method further comprises performing a WirelessLocal Area Network (WLAN) admission procedure, the method furthercomprises sending a probe request by a Mobile Station (STA) (102) on aWi-Fi channel; monitoring the channel by the STA (102) for a proberesponse from a WLAN BS (103) in range, and operating on the channel,wherein the probe response comprises of Service Set Identifier (SSID) ofthe WLAN BS (103), and supported data rates; attempting to join the WLANnetwork of the WLAN BS (103) by the STA (102), by sending an AssociationRequest; forwarding the request to the WNC (101) by the WLAN BS (103);deciding by the WNC (101) whether to allow the STA (102) to connect tothe WLAN BS (103); communicating decision of the WNC (101) to the STA(102) using an association response frame; transmitting identity requestmessages by the WNC (101) to the STA (102); sending a response frame tothe WNC (101) by the STA (102), upon receiving the identity requestmessages, wherein the response frame comprises an identifier for the STA(102); configuring data flows at the data plane nodes (103), the WLANBS, and the gateways by the WNC (101); obtaining an IP address from theDHCP server by the STA; and using the configured data flow path by theWLAN BS (103) for transferring the data towards the external PDN throughthe gateways.
 19. The method, as claimed in claim 1, wherein the methodfurther comprises of performing a WLAN to LTE network handover procedurefor a UE (102), the method further comprises configuring a gateway (GW)and the WLAN BS (103) by the WNC (101) such that there exists a datapath between the WLAN BS (103) with which the UE (102) is associated andthe GW; allocating an IP address to the UE (102) by the WNC (101) basedon DHCP discover and DHCP Response; setting up a RRC connection betweenthe UE (102) and the WNC (101) through a target LTE BS (103); forwardingan attach request to the WNC (101) by the UE (102); setting up dataflows between the WLAN BS (103) and the target LTE BS (103) to forwardthe data intended for the UE (102) towards the target LTE BS (103) bythe source WLAN BS (103); establishing an LTE connection aftercompleting attach procedure by the UE (102); configuring the GW tocreate data flow for the UE (102) towards the target LTE BS (103);deleting old data flows towards the source WLAN BS (103); inserting anend marker packet as the last packet towards the source WLAN BS (103) inDL by the GW, before deleting the old DL flow; forwarding all UEspecific UL data towards the target LTE BS (103) by the source WLAN BS(103) using a forwarding tunnel; inserting an end marker packet at theend to indicate the completion of transfer of all UE specific UL data bythe WLAN BS (103); deleting a UL data flow path for the UE (102) by thesource WLAN BS (103); forwarding an end marker notification received bythe target LTE BS (103) to the WNC (101); deleting the forwarding dataflows between the target LTE BS (103) and the source WLAN BS (103) forthe UE (102) by the WNC (101); and transferring of buffered and newUL/DL data from/to the UE (102) by the target LTE BS (103).
 20. Acommunication system comprising a Wireless Network Controller (WNC)(101) configured for managing communication for at least one deviceconnected to a plurality of Radio Access Technologies (RATs), whereinthe plurality of RATs comprise of at least one data plane node (103),wherein the at least one data plane node (103) in a RAT is configuredfor forwarding control plane messages to the WNC (101), upon the atleast one data plane node (103) receiving the control plane messages;and managing user plane data, wherein the at least one data plane node(103) manages the user plane data by forwarding the user plane data toat least one UE (102) and other data plane nodes (103), wherein the(WNC) (101) is further configured for receiving control plane messagesfrom the at least one data plane node (103); managing control planedata, upon receiving the control plane messages from the at least onedata plane node (103), wherein the WNC (101) manages the control planedata by exchanging at least one control plane message with at least oneentity, wherein the entity is at least one of other peer controllers,gateways and control plane nodes of other RATS; and managing the atleast one data plane node (103) by providing at least one configurationto the data plane nodes (103) for the flow of data through the dataplane nodes (103).
 21. The WNC, as claimed in claim 20, wherein the WNC(101) further comprises a Software Defined Networking (SDN) middleware(401), a RAT specific control layer (402) for each RAT supported by theWNC (101), and an application layer (403), wherein the SDN middleware(401) comprises a RAT abstraction module (401 a); a flow configurationmodule (401 b); and an interface (401 c) towards peer controllers,gateways and control plane nodes of other RATS.
 22. The WNC, as claimedin claim 21, wherein the RAT abstraction module (401 a) is configuredfor translating RAT specific details into a message format.
 23. The WNC,as claimed in claim 22, wherein the flow configuration module (401 b) isconfigured for configuring and setting-up traffic flows using thetranslated message format.